It may be significant that the rigs aboard Speedwell and Pete Hill's 2 catamarans are low aspect rigs: Reddish types or a unique, wishbone/split junk design in Oryx. Pete Hill ,who designed and built all 3 of these, evidently thinks there are limits to the height of masts stepped in tabernacles.

It's also worrth noting that the pivot bolt in these designs doesn't pierce the mast, which would weaken it, but passes through a tube fixed to its aft side. Practical Junk Rig gives advice on the design of a tabernacle.

Have a look at Pete's "Oryx" tabernacle in the photo gallery.

Timothy, tabernacles have been successful aboard Speedwell of Hong Kong, a Vertue that has cruised extensively in the N and S Atlantic Oceans and Catamarans China Moon and Oryx, in which Pete Hill has made passages in the Southern Ocean.

These wooden tabernacles are keel stepped and project high enough above deck to give adequate support to the mast: at least 10% mast length.

Asmat

Is there any particular reason mast tabernacles are not favored for junk rigs? The one in I recently designed is for a 19' daysailer/weekender that will initially get a balanced lug rig with a flat-cut mizzen offset in the stern. I'm fairly sure that a tabernacle can be designed with most, if not all the strength of a keel-stepped arrangement. There are few advantages to a tabernacle for blue-water cruising. Tabernacles tend to be much more complex in design, and don't save any cabin space, as the part needs to be supported by a "Sampson Post" which is as large or larger than a keel step. The arrangement shines in my particular environment, however. To go anywhere off Lake Champlain, I've got to deal with height restrictions. Quite frankly, stepping and unstepping a keel-set mast is an enormous pain, costly, and takes a lot of planning and delays. With a tabernacle and a gallows, it is possible to drop and raise with relatively simple hardware. Thoughts?

I went over to the water-jet shop today to pick up the parts. They are beautiful. I dropped them at my welder's today, and from there will go for powder coat.  I drove past the place three times, as they don't particularly advertise. I pulled down through the snow on a country road and found a tiny sign on the door that said "Water Jet Shop." The clue was the massive three-phase lines leading in. Jesse, the son of the proprietor, and the current production manager took me in and gave me a good tour. These folks can take up to a 10' x 5' plate and cut to +/- .005. They have a 60 ton press brake as well, and a variety of other tooling. They can subcontract various machining and finishing services. When I get around to designing the mast partners or perhaps a tabernacle for my steel Vita 30, these folk will have the work. 

I did the same thing with the panels for my split junk rig fabrication. Created the panels in a spreadsheet then CAD prog including the 1 inch overlap.

Exported DXF files which were emailed to http://wyckam.com/ in Portland, OR. They are a sailmaker/custom fabric design shop and have a CNC fabric cutter. You can choose the fabric you wish in house or make a quantity buy at another vendor and ship the roll to them.

This approach to the SJR fab suited me 'cause I did not have access to floor space for lofting. When the individual panels arrived in the mail all I had to do was paste the correct ones together along the 1" overlap with acrylic sticky tape, then sew the seam. All the fabrication (550 ft^2 sail) was done in the small space of the forepeak and salon of a 34 ft sailboat.

The SJR is especially amenable to small space construction 'cause it's in 3 pieces: jiblets, main, top panel(s) that only come together when battens are installed, i.e. launch day. The 3 pieces are never sewn together so there is no massive single sail (51 m^2 in my case) to deal with.

robert self